Shelf divider



FIG. 1 is a top, front, and left side perspective view of a shelf divider showing my new design, the broken-line depiction of the shelf and legend being for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a bottom, rear and right side perspective view thereof;

FIG. 3 is a left side elevational view thereof; and

FIG. 4 is a rear elevational view thereof. 

The ornamental design for a shelf divider, as shown and described. 